Andy,
I am in exactly the same boat - 7 years airforce (NZ), 34 and just finishing my eng licences now. I finished my CPL last year and am looking at Canada late this year to get some flying work.
One thing I have learnt though is that some employees will promise you the world when it comes to flying but will ultimately "use" you for your engineering abilities so you will have to make sure you don't get trapped into wrenching the for the rest of your days if you want to fly.
I believe the engineering will be an excellent backup for off season work or if you just get short on cash while looking for work overseas. Flying has been a lifelong ambition for me and I am glad I have done the CPL and can now just start to see doors opening.
If you are single and can earn good coin to pay for the flying then I say go for it if it is going to make you happy, Life is too short to be unhappy in your job.
One thing I can recommend is perhaps buying a share in a training helicopter - I did here in NZ and it saved me about $260 per hour and I never looked back.
Good luck HK